1. Field of the Invention
The present invention relates to an apparatus for storing data and telecommunication cables in storage cabinets for emergency deployment. Data and telecommunication transmission apparatus includes, among other things, hardwire or fiber optic cable transmission lines for transmitting electronic signals in a data stream. Hereafter, the use of the term telecommunications in this specification includes data transmission over the same signal transmitting infrastructure.
More particularly, the present invention relates to an enclosure or case for the storage of predetermined lengths of fiber optic telecommunication transmission cable on reels with connectors at the ends thereof so that the cables can be unreeled and patched together in an emergency to bypass either remotely or locally located inoperative equipment at a telecommunications switching center.
Still more particularly, the present invention relates to an enclosure or case for reels of lengths of fiber optic cable which can be stored in pre-existing cabinet racks forming an emergency depot of banks of stored fiber optic cables. The cables are of a predetermined length and can be linearly extracted from the cabinets which are of a specific configuration and size to fit into a specific sized receptacle.
Specifically, the present invention relates to a flat rectangular box of predetermined dimensions and front panel configuration forming an enclosure to meet a specific design criteria for mounting in pre-existing racks and having a specific capability of sliding horizontal reciprocating relation through an aperture having a fixed width and height formed in a faceplate of a vertical rack. The box contains a rotatable reel holding a maximum length of fiber optic telecommunications for the interior volume of an enclosure which can fit in the pre-existing racks. The cable mounted on the reel can be rapidly extracted in an emergency and utilized to bypass damaged or inoperative apparatus or equipment. A multiple of the enclosures are stacked in cabinets having receptacle racks for the enclosures creating an emergency response facility.
2. Description of the Prior Art
The use of storage enclosures for spare or reserve communications cables for the purpose of providing emergency connections in the event of equipment breakdown is known in the prior art in one form or another. In a substantial number of facilities, a specific design criteria has been adopted for racks which hold a plurality of flat rectangular drawers forming cable enclosures. However, despite the numerous designs, structures, and forms of the apparatus disclosed by and utilized in the prior art, which have been developed for the accomplishment of the specific objectives, purposes, and requirements of the adopted design criteria, for ready cable storage for emergency response and deployment, the devices, apparatus, and methods which have been heretofore devised and utilized to accomplish these goals consist basically of familiar, expected, and obvious combinations of configurations and arrangements of well-known apparatus which have substantial defects. They do not meet the requirements of the fixed parameters for these devices for reliable and efficient operation. This will become apparent from the following consideration of the closest known and relevant prior art.
Telecommunications transmission lines are an important part of the infrastructure of almost all of the developed countries in the world as well as most of even the underdeveloped countries. Any breakdown is tantamount to a catastrophe, and as a result, all data and telecommunications transmission companies require backup systems. This has become especially important in view of the terrorist threats to the United States as well as to other countries having terrorist communities. The telecommunications networks must be prepared to respond to external emergency situations apart from, and as well as, anticipated and unexpected breakdowns in the network itself. An operations service center containing switching and server equipment is an especially vulnerable hub of the telecommunications network.
In anticipation of these possible internal and external threats to the continuity of the network, certain facilities have been provided with banks of fiber optic cable reels of a predetermined configuration and design criteria containing an optimum preselected length of 50 meters of standard 48 fiber cable which can be quickly pulled out of storage to patch across either remotely or locally located inoperative equipment to keep the network interconnected. The presently employed equipment utilizes cable reels mounted in drawers, in the form of flat rectangle boxes, which are stored in banks of cabinet racks.
Connectors are secured to both ends of the fiber optic cable wound on the reels: the fixed end of the cable is usually connected to a receptacle on the faceplate of the enclosure and the free end of the cable to a remote receptacle or to another cable. The present standard in the art utilizes male and female industry-standard MTP connectors which employ precision guide pins to align the internal fibers of the cables to transmit the data stream. MTP connectors are coupled together inside an industry-standard MTP adapter which engages the connectors to hold the two ends of the connectors together in alignment. An adapter is a coupling receptacle and is usually mounted in a faceplate of an enclosure or it can free float where it interconnects two cables. The two mating connectors are plugged into an adapter from opposite sides of the faceplate or, if free floating, from the opposite ends of the adapter.
For deployment, the free end of a reel stored cable is positioned by an operator to project through the faceplate of an enclosure whereby it can be grasped and pulled to reel out the fixed length of cable from the enclosure. A multiple of the cables can be interconnected, patched, or jumpered to bypass the inoperative equipment or to interconnect remotely located equipment.
There are many problems with the present standardized design of the cable storage enclosures which were created initially to meet the design criteria. The prior art enclosures containing a full complement of cable are very heavy. For installation in a storage rack, it requires two persons to lift and hold a drawer in position so that securement screws can be set at the corners to fix the drawers in the rack. The drawers are provided with ball bearing slides which are secured in the cabinet by the corner screws. The drawers can be partially slid out of the racks on these slides in order to rewind the cables onto the reels after they have been deployed in an emergency or alternatively for testing, repair, or inspection. The drawers can also be partially slid out to provide access to the cable for commencing deployment.
The construction of the cable reels of the prior art design is comprised of two metal disks which are separated by central standoff pins forming a segmented circle in the center of the reel. The problem with using the standoff pins, which presumably was employed as the simplest or cheapest form of construction, is that if the cable is wound to tightly on the reel, the cable is bent sharply around each standoff pin, and that can cause fiber breakage in the fiber-optic cable.
The cable reels are mounted in the drawers on lazy susan turntables which are secured to the bottoms of the boxes under the reels which hold the fiber optic cable. The lazy susan supports the reel and allows it to turn freely to wind and unwind the cable onto or from the reel. Unfortunately, the lazy susan also allows the reel to continue turning after tension on the cable, utilized for pulling it off the reel, has ceased or abated thereby permitting the layers of cable to loosen within the reel. This effect cannot be reversed without pulling further cable off the reel until the slack has been removed and then the cable rewound. No mechanisms have been designed for incorporation into the enclosures to cure this problem.
The side mounted drawer slides narrow the width of the drawer, and the height of the lazy susan in the drawer reduces the width of the reel which can be put in the drawer, whereby these devices occupy storage space in the allotted drawer space or volume, and the 50 m designated lengths of fiber optic cable cannot all fit onto the standard reels. The excess must be gathered and tucked into the corners of the box, and velcro straps are used to hold the excess cable tightly in the remaining space. As a result, the cable cannot be quickly reeled from the front faceplate of the box as designed: the drawer must be slid out of the rack and opened to access the tied sections of cable, and release them, in order to extract the excess cable from the corners before the rest of the cable can be pulled off of the reel through the faceplate. Thus, the enclosures do not function as designed.
Apart from the design problems, there are numerous operational problems which have become apparent which essentially are also design problems. In addition to the lack of cable storage volume in the drawer, caused by the presence of the drawer slides and the lazy susan, the space between the peripheral edges of the reel and the sides of the enclosure has been such that the outer layer of cable will jam in between the reel sides and the enclosure side panels during rewinding because not all of the cable will fit on the reel. This causes compression of the cable when the cable is wound too tightly onto the reel trapping it between the wound cable and the side panels and thereby possibly causing crushing and damage to the individual fibers. The wedging also causes the cable to stick between its own layers and or the sides of the reels, as well as the sides of the enclosure, and prevents the cable from unwinding freely if it has been wound up too tight. As a heavy reel continues turning pass the point of jam, because angular momentum of the lazy susan allows continued rotation of the heavy reel, tension applied to the cable by pulling on it can jerk the cable out of the jam point and back bend the internal fibers in a direction opposite to its initial wind direction thus causing the back bend and possible fractures in the cable fibers.
The primary problem is that the design does not permit the storage drawers to function as intended. The cable cannot be pulled out of the drawer by the projecting cable pulling eye connector on the free end of the cable when it is disposed or positioned within the enclosure front panel because the drawer must be opened to permit the cable tucked into the each of corners to be released and fed out through the front aperture before it can be pulled off the reel as designed. More of a problem, however, is the fact that the cable tucked into the corners is subjected to severe bending which could cause the individual fibers in the fiber-optic cable to crack or fracture. This is a severe operational defect which could render the cables partially if not wholly inoperative. Making the drawers larger is not an option because the cabinet racks are existing installations in the facilities. Likewise, storing less than the optimum 50 m length of 48 fiber cable on the reels renders the emergency design unusable. All of the parameters of the design are laid out based on 50 m patch cable lengths to create inoperative equipment bypasses and network interconnects.
The prior art enclosure design has a locking pin mechanism wherein a spring-loaded locking pin is mounted in the box and secured to the lower side plate of the reel by a screw. The pin is formed to project through the cable reel bottom surface to engage a hole in the bottom surface or pan of the drawer. When the pin is engaged with both the reel and the enclosure, it locks up the cable reel and prevents it from rotating in either direction. Due to the play inherent in the bearings of the lazy susan, combined with an insufficient space for an adequate length of pin for positive engagement, the pin does not always engage both holes, thus preventing continuous positive lock up of the reel.
The standard design of the storage racks for containing the prior art reel enclosures is such that the rectangular flat drawers are oriented horizontally and the reels lie flat in the storage racks with their axes of rotation oriented vertically. As a result, gravity affects winding of the cable on the reels whereby it is biased to collect on the lower reel wall or plate until tension on the cable causes it to climb up the wound cable and fill the reel. The presently existing prior art design has clearance of slightly more than ¼ inch under the reel due to the lazy susan. That space allows the cable to wind off the edge of the reel and slip under the reel lower plate and become wedged between the reel and the bottom pan of the drawer and jam thereunder and prevent the lazy susan and reel from turning to either wind or unwind the cable. It also has the effect of crushing the cable and damaging the individual fibers.
To prevent the cable from winding out from the center of the spool, on the lower side wall of the reel, and off the lower outer edge of the reel before it is full, the prior art has employed two rollers mounted in the drawers at the edges of the cable reel to keep the cable from pushing out and around the edges of the reel in the corners of the drawer and dropping down and slipping under the bottom panel of the reel in the vertical space necessitated by but unoccupied by the lazy susan. The two rollers are provided set 180 degrees apart in the corners of the drawers and against the edges of the reel. Since not all the cable will fit on the reel, binding of the cable between two rollers and the cable already wound on the reel can occur when the reel is full but before all of the cable is wound on the reel. Damage to the cable fibers occurs if one continues to forcefully wind the cable on the reel. The roller guides are an expensive and unnecessary correction for a problem which should not exist.
A rewind handle is provided with each enclosure which is held in the drawer by velcro straps on the inside thereof. It can be released and attached to the reel to enable rewinding of the cable onto the reel after the need for the cable to be extended in an emergency, or for repair, or after a test situation, has abated. The location of the attachment point for the handle to the reel is proximate the center of the reel for convenience but such that the mechanical advantage is at a minimum. The force required to rotate the reel is unnecessarily excessive, and there is no feedback to the operator or feel as to how tight the cable is being rewound onto the reel. Thus, the cable can be caught on interfering surfaces and projections throughout the cable path during rewind. In such circumstances, when the cable is snagged during rewind, and the operator continues the rewind process, a kink or excessive tension on the cable can cause damage to the cable.
The cable reel enclosure contemplated according to the present invention departs substantially from the conventional concepts and engineering design taught and employed by the prior art to meet the established design criteria. In doing so, the present invention provides an apparatus primarily developed for the purpose of increased utility and functionality to overcome the problems described above and to improve upon the design in such a manner as to comprise a new and unobvious enclosure unit which fully satisfies the initial design parameters. It accomplishes the result in a different and improved manner thereby producing a more versatile reel enclosure which is also lighter and less expensive to manufacture. The enclosure of the present invention more accurately achieves the desired functions of the apparatus and accomplishes the specific original objectives for an installed emergency fiber optic cable storage enclosure without jamming of the cables during extraction or the need to release the corner cable collections before extracting the cable.
The new design can also be used in more permanent applications where there is an unknown cable length or connector type required: e.g., where office equipment needs to be relocated easily; where there is a need for “reusable” cable; in trade show booths and emergency restorations; or anywhere untrained labor will install the cable.